The present invention relates to a surgical tool, and to a mechanism for its operation. More particularly, but not exclusively, it relates to such a tool having improved ease of manual control.
Over the past 20 years, much effort has been applied to the development of specialised surgical instruments which allow complex procedures to be performed with predictable outcome. (For example, see U.S. Pat. No. 6,887,252; U.S. Pat. No. 6,056,735; U.S. Pat. No. 6,063,050 and U.S. Pat. No. 6,468,286). Many of these devices are designed to manipulate and dissect biological tissues. These devices may be manually operated or alternatively may incorporate a powered element designed to deliver an enhanced tissue cutting performance with significant haemostasis: see for example U.S. Pat. No. 5,938,633; U.S. Pat. No. 5,322,055 and U.S. Pat. No. 6,352,532. Both ultrasound and RF electrical currents are commonly used to energise such instruments. The above instruments also embody ergonomic features associated with basic hand instruments providing core surgical needs.
A review of modern clinical trends related to the field of general surgery indicates an expectation on the part of specialists in minimal invasive surgery that any instruments offered in the future will incorporate significantly enhanced handpiece designs, in order to enable the surgeon successfully to undertake long, intricate procedures without experiencing fatigue, which could compromise the surgical outcome.
There have been past attempts to provide relevant functionalities addressing the requirements for controlling the cutting plane orientation, combined with accurate tissue targeting. These have been limited by inadequate mechanism designs, which impose physical constraints on the surgeons' ability to operate freely. For example, mechanisms have been proposed in which the cutting plane of the surgical tool is rotated by pushing with the surgeon's fingertip. Accurate control is difficult, and even the most dextrous surgeons find that they can rotate the cutting plane in one direction but not rotate it back in the other direction.